1. Technical Field
The disclosure relates to a joining method, and in particular, to a method of joining superconductor materials.
2. Related Art
Based on the current industrial technologies, superconductor materials are joined by using copper metal as an assistant joining material. However, by using the joining type, a produced high-temperature superconductive lead of yttrium barium copper oxide (YBCO) can merely have a maximum length of 500 meters. If the length of the superconductive lead is further extended, the performance of a superconductive product thereof is affected after being used for a long time. The main reason is that although the resistance value of the copper metal that is used to join superconductor materials is not high, the copper metal has a certain resistance value after all. Therefore, heat may be inevitably generated during a long time of running to cause the consumption of energy, even make the superconductive lead lose its conductivity. Hence, the whole quality of the superconductive transmission line is affected.
Apart from this, high-temperature superconductor materials are almost in a complex structure of ceramic oxide materials. For the bonding between conventional ceramic materials, a fluxing agent may be used to lower a bonding temperature of ceramic (lower than a sintering temperature thereof). However, although the ceramic can be bonded together, the interface structure is changed, and thus is incapable of being the same as that of the origin material. Therefore, a rather large resistance value definitely exists on the bonding interface.